Comparison of shear bond strength of rebonded brackets prepared with different methods of resin removal: an in vitro study

Abstract

Aim: Clinicians and researchers have always made every effort to achieve proper bonding between the surface of the tooth and the rebonded orthodontic brackets in order to prevent the re-fracture failure of orthodontic pressures throughout treatment. The aim of this study was to determine the bond strength of rebonded brackets by four adhesive removal methods. Materials and methods: Seventy-five orthodontic brackets were bonded to the extracted first premolar teeth and then debonded. Fifteen of these teeth were rebonded to new brackets after adhesive removal and were named as the control group. Sixty debonded brackets were divided into four groups by means of resin-removal: laser, burr, sandblast, and direct flame. These recycled brackets were re-bonded to the teeth with the same basic bonding methods. The shear bond strength (SBS) was measured at the speed of 0.5 mm/min and the data were analyzed using ANOVA and post hoc tests (α=0.05). Results: SBS was significantly different in all four groups compared to the control group (p<0.05). The burr and sandblast groups had the lowest levels of SBS. Although the laser and flame groups had the highest levels of SBS, they did not show a significant difference (p=0.99). Conclusions: 5W Er:YAG irradiation and direct flame due to relatively good bond strength can be recommended as proposed methods for orthodontic brackets recycling.